Audio Latency changes during streaming

[Lumo]

Hey guys, I have a big problem here.
I'm using OBS Studio with 2 Audio-Interfaces which I know I can synchronize by using the advanced audiosettings and change the sync offset.
The thing is that the latency seems to change randomly after a while.
Its about +-50ms which is way too much when playing live music and I have no Idea what is the cause of this problem.
I do my tests by routing the main output of interface1 directly into the input of interface2 and record some metronome clicks in interface1- so I can clearly hear if the click is in phase or not. Sometimes I hear two clicks with a delay of 5 to 50ms which is stable for a while but changes randomly when I restart the recording/stream - and in my last live stream it changed even during the stream :(
I tried
- older versions of obs,
- turn on/off the "device timestamp" on both devices (or only on one of both),
- sometimes when I restart the software the latency changes
- increasing the number of samples / device block size of each audio interface in my DAW using the default-control-panel for the devices (no clue if it's used in obs then but it doesn't help)
Both audio interfaces on their own work perfect in my DAW and I think a latency change during recording would break everything down, so there must be something in OBS I guess.

Any ideas would be helpful
Lumo

 

[garrettscott1997]

I have this problem for live-streaming using logic as my daw. I cannot figure out why it keeps changing throughout a service either.. it is sooo frustrating.

 

[Lumo]

Really no one has an idea what's the latency problem? Any audio-related obs-programmer here?

 

[konsolenritter]

No Dev,

but i wrote a post couple of months ago regarding these issues (especially if you use more than one audio device at once):

Separate Audio capture devices for separate scenes

I have two scenes which are cameras in two rooms and I want to switch between them. I want a stereo audio feed from each room to go with the camera feed. Am I right that OBS doesn't handle multi-channel sound cards particularly cleanly, so rather than buying a 4-input sound card and having...

obsproject.com

It points to another post where i described whats going on.

I know I can synchronize by using the advanced audiosettings and change the sync offset.

Not exactly. The devices aren't sync'd that way. You just set an offset to compensate for delay under the assumption, that both crystals are synchronized already (hence constant offset).

Are both devices you use separate USB devices? Every stop and (re)start of sampling or playing over usb depends on different timing conditions on the usb bus, wether its busy or not (and some driver-dependent constraints within the computers os)...